Gel: A generic extensible language

Abstract. Both XML and Lisp have demonstrated the utility of generic syntax for expressing tree-structured data. But generic languages do not provide the syntactic richness of custom languages. Generic Extensible Language (Gel) is a rich generic syntax that embodies many of the common syntactic conventions for operators, grouping and lists in widely-used languages. Prefix/infix operators are disambiguated by white-space, so that documents which violate common white-space conventions will not necessarily parse correctly with Gel. With some character replacements and adjusting for mismatch in operator precedence, Gel can extract meaningful structure from typical files in many languages, including Java, Cascading Style Sheets, Smalltalk, and ANTLR grammars. This evaluation shows the expressive power of Gel, not that Gel can be used as a parser for existing languages. Gel is intended to serve as a generic language for creating composable domain-specific languages